BUG: IPC socket drops messages, ignores LINGER

What pyzmq version?

25.1.0

What libzmq version?

4.3.3

Python version (and how it was installed)

3.11.5

OS

Ubuntu 22.04

What happened?

Setting linger option for the sender doesn't block when the socket/context are closed. It exits immediately, but receiver doesn't end up reading all messages, so something is amiss.

It only seems to manifest if I set HWM, which I'm guessing is because without the limit libzmq is able to buffer everything in the client almost immediately.

Code to reproduce bug

import zmq, threading, time

def server():
    linger = 1000*60
    ctx = zmq.Context()
    sock = ctx.socket(zmq.PAIR)
    sock.setsockopt(zmq.LINGER, linger)
    sock.bind("ipc:///tmp/lingertest")

    print("server ready")
    for i in range(10):
        sock.send_json(i)
        print("server send", i)

    sock.close(linger)
    ctx.destroy(linger)
    print("server exiting")

def client():
    ctx = zmq.Context()
    sock = ctx.socket(zmq.PAIR)
    sock.setsockopt(zmq.RCVHWM, 1)
    sock.connect("ipc:///tmp/lingertest")

    print("client ready")
    while True:
        time.sleep(.5)
        i = sock.recv_json()
        print("client recv", i)
        if i == 9:
            break

    sock.close()
    ctx.destroy()
    print("client exiting")

threading.Thread(target=server).start()
threading.Thread(target=client).start()

Traceback, if applicable

n/a

More info

In this case I'm using a pair socket, so easy enough to have the server/client communicate when each are done instead of relying on linger.

zeromq / libzmq